Perfluoro-1-cycloalken-1,2-ylene-diphosphoryl compounds

ABSTRACT

A perfluoro-1-cycloalken-1,2-ylenediphosphoryl halide of the formula WHEREIN X is selected from the group consisting of chlorine and bromine, R&#39;&#39; is an organic radical, m is from 2 to 4, and n is from 0 to 1.

I United States Patent [151 3,681,448 Frank et al. [451 Aug. 1, 1972PERFLUORO-l-CYCLOALKEN-l,2- [56] References Cited YLENE-DIPHOSPHORYLCOMPOUNDS OTHER PUBLICATIONS [72] Inventors: Arlen W. Frank, Grandisland, Kosolapofn organophosphoms Cmpd p. 61' Q1) 412 N.Y.; Charles F.Baranauckas, plKs Memphis Primary Examiner-James A. Patten [73]Assignee: Borg-Warner Corporation, Chicago, Assistant Examiner-E. JaneSkelly lll. Attorney-William S. McCurry and Roger A. 22 Filed: Sept. 8,1969 schmege [21] Appl.No.: 870,802 [57] ABSTRACT A perfluoro- 1-cycloalken-1 ,Z-yIenediphosphoryl ha- Related U.S. Application Datalide of the formula [62] Division of Ser. No. 438,105, March 8, 1965, xo o x Pat. No. 3,501,555. g M 52 us. Cl ..260/543P mm E Yam. [5]] Int.Cl. ..C07f 9/28 of Search P h i x is elected from he gxoup consisting ofchlorine and bromine, R is an organic radical, m is from 2 to 4, and nis from O to l.

3 Claims, No Drawings PERFLUORO- l-CYCLOALKEN-l ,Z-YLENE- DlPl-IOSPHORYLCOMPOUNIE This is a division of our parent application, Ser. No.438,l05, filed Mar. 8, 1965, now US. Pat. No. 3,501,555 issued Mar. 17,1970.

This invention relates to novel halogenated organophosphorus compoundsand a method for preparing the same. More particularly, it relates tocyclic perfluoroolefins containing two phosphoryl (P-) groups onadjacent unsaturated carbon atoms.

it is an object of this invention to prepare novelperfluoro-l-cycloalken-l,Z-ylenediphosphoryl compounds. Other objects ofthe invention will be apparent from the following detailed description.

The novel compounds of this invention have the formula wherein R and Rare organic substituents independently selected from the groupconsisting of alkyl and substituted alkyl having from one to 12 carbonatoms, the most preferred of these have one to six carbon atoms; aryl.and substituted aryl having from six to 15 carbon atoms, the mostpreferred of these have six to nine carbon atoms; aralkyl andsubstituted aralkyl having from seven to 20 carbon atoms, the mostpreferred of these have seven to carbon atoms; alkenyl and substitutedalkenyl having from two to 12 carbon atoms, the most preferred of thesehave two to six carbon atoms; cycloalltyl and substituted cycloalkylhaving from three to 15 carbon atoms, the most preferred of these havethree to eight carbon atoms; and heterocyclic and substitutedheterocyclic having from one to 15 carbon atoms, the most preferred ofthese have one to eight carbon atoms, m is from 2 to 4, and n is from 0to 2.

The substituents present on the alkyl, aryl, aralkyl, alkenyl,cycloalltyl, and heterocyclic radicals may be halogen, nitro, amino,substituted amino, hydroxy, alkoxy, mercapto, carbonyl, carboxy, cyano,and the like.

in accordance with the practice of this invention it has been found thatthe novel compounds of this invention can be prepared in excellentyields by reacting a perfluorocycloalltene (hereinafter referred to ascycloalltene) selected from the group consisting of 1,2-dichloroperfluorocycloalkene and l,2-dibromoperfluorocycloalkene, themost preferred of these include I ,2-dichlorotetrafluorocyclobutene,l,2'dichlorohexofluorocyclopentene and1,2-dichlorooctafluorocyclohexene, with a phosphorus-containing compoundof the formula P-oru wherein R and R are as previously defined, Risselected from the group consisting of alkyl and substituted alkyl havingfrom one to 12 carbon atoms, the

most preferred of these have one to six carbon atoms; aralkyl andsubstituted aralkyl having from seven to 20 carbon atoms, the mostpreferred of these have seven to l0 carbon atoms; alkenyl andsubstituted alkenyl having from two to 12 carbon atoms, the mostpreferred of these have two to six carbon atoms; cycloalkyl andsubstituted cycloalkyl having from three to 15 carbon atoms, the mostpreferred of these have three to eight carbon atoms, and n is from 0 to2.

Typical phosphorus-containing compounds which may be employed in thepractice of this invention include, triesters of phosphorous acid suchas trimethyl phosphite, triethyl phosphite, triisopropyl phosphite,tributyl phosphite, diethyl butyl phosphite, ethyl propylene phosphite,methyl phenylene phosphite, tris (2-chloroethyl) phosphite, triallylphosphite, diethyl phenyl phosphite and tris (2-butoxyethyl)phosphite;diesters of phosphonous acids such as diethyl ethylphosphonite, diethylphenylphosphonite, dibutyl hexylphosphonite, and bis(2-chloroethyl)benzylphosphonite; and esters of phosphinous acids such asethyl diphenylphosphinite, butyl dihexylphosphinite, allyldiethylphosphinite, and the like.

The following equation, wherein the cycloalkene is al,2-dichloroperfluorocycloalkene and the phosphoruscontaining compoundis a dialkylarylphosphonite, illustrates generally this invention:

2 1= 0n Cl 1 r 0 R0\0 0/012 Wi 2 mm R: c l)- B! In the practice of thisinvention the cycloalkene and the phosphorus-containing compound may bereacted in any suitable reaction vessel, so that, the reaction may becontinuous, intermittent, or batch-type. The reactants may be reacted oradded to the reaction zone simultaneously, as for example, when thereaction is carried out continuously in a column, or in any sequence, asfor example when the reaction is carried out batchwise, withoutdeparting from the scope of this invention. Conveniently, thephosphorus-containing compound may be added to the cycloalkenepreviously preheated to reflux at a rate sufficient to maintain a steadyevolution of the alkyl halide.

in general, the reaction takes place at temperatures ranging from 0 200C., preferably from 30 180 C., and most preferably from 50 120 C.Atmospheric pressure is usually employed, but pressure in excess or lessthan atmospheric may also be employed. For example, when R' is methyl orethyl, so that a gaseous byproduct is formed, the reaction isconveniently carried out at atmospheric pressure, preferably at atemperature in the range of 50 C and the boiling point of thecycloalkene. When R is such that the organic halide formed is notvolatile, the reaction is conveniently carried out in a sealed vesselunder autogenous pressure.

If desired, the reaction may be carried out in the presence of anorganic solvent, such as a hydrocarbon or an alcohol, although the useof a solvent is not ordinarily essential. Removal of the evolved organichalide may be facilitated if the solvent chosen is such as to 3 permitazeotropic distillation. Typical examples of such solvent includetoluene, xylene, and the like.

The relative amounts of the reactants employed may vary, although it isdesirable that excesses of either reactant be avoided. The molar ratioof phosphorus containing compound to cylocalkene may be in the range of0.05 mole to 6 moles of phosphorus-containing compound per mole ofcycloalkene, preferably between 0.5 mole to 3 moles ofphosphorus-containing compound per mole of cycloalkene, the mostpreferred molar proportion being a substantially stoichiometricproportion of 2 moles of phosphorus-containing, compound to 1 mole ofcycloalkene.

After the reaction has been conducted for a period of time sufficient toobtain the maximum yield, generally from l minutes to 10 hours, thereaction product is separated from the reaction mixture. The separationmay be accomplished by any suitable means which include distillation,extraction, and the like.

The compounds of this invention may be converted by suitable methods touseful derivatives. For example, the diphosphonate esters of thisinvention may be hydrolyzed to yield diphosphonic acids of the formula 0O (HOhi T i (OH):

O I)m wherein m is from 2 to 4. While the diphosphinate esters of thisinvention may be hydrolyzed to yield phosphinic acids of the formulawherein X is selected from the group consisting of chlorine and bromine,R is an organic radical as previously defined, m is from 2 to 4, and nis from 0 to 1.

It is also within the scope of this invention to prepare unsymmetricaldisphosphoryl compounds of the formula (IUD)... 0 O (OHM-s wherein R andR are independently selected from the group consisting of R and R aspreviously defined, and RandR' areaspreviouslydefined,misfrom2to4, and nis from 0 to 2.

These unsymmetrical diphosphoryl compounds may be prepared by employingtwo or more phosphorus containing compounds previously described as thereactants in the process of this invention.

The preferred embodiment for the preparation of the unsymmetricaldiphosphoryl compounds comprises reacting aZ-haloperfluoro-l-cycloalken-l-ylphosphoryl compound (hereinafterreferred to as cycloalkenemonophosphoryl) of the formula wherein X isselected from the group consisting of chlorine and bromine, R and R areorganic radicals as previously defined, m is from 2 to 4, and n is from0 to 2, with a phosphorus-containing compound of the formula (m b-n P-ORwherein R and R are independently selected from the group consisting ofR and R as previously defined, R' is as previously defined, and n isfrom 0 to 2.

As the cycloalkene monophosphoryls there can be used compounds such asdibutyl-Z-chlorohexafluorol cyclopenten-l-ylphosphonate,dimethyl-Z-chlorohexafluoro-lcyclopenten-l-ylphosphonate, ethyl-2-chlorohcxafluorol -cyclopentenl -ylphenylphosphinate,diethyl-Z-chlorohexafluoro-l-cyclopentenl ylphosphonate, and the like. Aprocess for the preparation of the above-described compound is disclosedin a copending application filed of even date herewith, and illustratedherein by Example 13.

The reaction conditions of the preferred embodiment are as previouslydescribed wherein the reactants are present preferably in asubstantially stoichiometric ratio of l to 1.

The compounds of the invention are generally useful as leveling agentsfor floor waxes, where they also contribute a resistance to waterspotting; as plasticizers for polyvinyl chloride resins; as cellmodifiers for urethane foams; as surface active agents; as insecticides;and as additives for extreme pressure lubricants, where their useimparts improved wear properties to the lubricants. The compounds areparticularly useful as metal extractants and sequestering agents.

The following examples are presented to illustrate the novel compoundsof this invention and their preparation. It is to be understood that theexamples are not to be construed as limiting the invention except asdefined in the appended claims. All temperatures are in degreescentigrade all parts are by weight, unless otherwise mentioned.

EXAMPLE 1 A mixture of 24.5 parts of 1,2-dichloro-3,3,4,4,5,5,-hexafluorocyclopentene and 33.2 parts of triethyl phosphite was heatedto reflux and maintained at reflux until the evolution of ethyl chloridesubsided (30 minutes). At the end of this time a test for unreactedphosphite was found to be negative. The resulting solution wasdistilled, giving 6.5 parts (20 percent) of diethyl ethylphosphonatedistilling at 65-135 C, at l millimeter of absolute pressure, followedby 33.4 parts (74 percent) of tetraethyl-3,3,4,4,5,S-hexafluoro-l--cyclopenten-l,Z-ylenediphosphonate, boiling point 122148 C, at 0.4millimeter of absolute pressure. This product is a new compound havingthe structure A portion of this product was redistilled, providing ananalytical sample, boiling point l1l-112 C, at 0.1 millimeter ofabsolute pressure, and refractive index (nD) 1.4167. The productcontained 35.09 carbon, 4.59 hydrogen, 25.27 96 fluorine, 13.3phosphorus. The calculated percentages of these elements in C l-l F mP,are 34.83 carbon, 4.50 hydrogen, 25.43 fluorine, 13.82 phosphorus.

EXAMPLE 2 This example illustrates the effect of a nonstoichiometricratio of the reactants on the course of the reaction of a phosphorusester with a cycloalkene. 33.2 parts of triethyl phosphite were addeddropwise over a 14 minute period to 49.0 parts of 1,2-dichloro- 3 ,3,4,4,5 ,S-hexafluorocyclopentene at reflux, followed by refluxing untilthe ethylchloride evolution subsided. At the completion of the reactionthere were recovered 2.5 parts (8 of diethyl ethylphosphonate, 33.0parts (37 oftetraethyl-3,3,4,4,5,5-hexafluoro-l-cyclopenten-1,2-ylenediphosphonate,and 24.1 parts (49 of unreacted l,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene. When the order ofaddition was reversed, the cycloalkene being added to the methylphosphite at 90100 C, the products were 10 9b of diethylethylphosphonate, 35 k of tetraethyl- 3 ,3,4,4,5 ,5-hexafluorol-cyclopentenl ,2- ylenediphosphonate, and 54 b of unreacted 1,2-dich1oro-3,3,4,4,5,S-hexafluorocyclopentene.

lt is seen that the use of a 1:1 molar ratio of the reactants does notresult in the formation of a monophosphonate ester.

EXAMPLE 3 A mixture of 24.5 parts of l,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene and 24.8 parts of trimethyl phosphite was heatedto reflux and maintained at reflux until the gas evolution subsided anda test for unreacted phosphite was negative (7.5 hours). Distillation ofthe resulting mixture gave 11.] parts (45 of unreactedl,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene, 13.8 parts (56 ofdimethyl methylpho'sphonate, and 15.5 parts (40 oftetramethyl-3,3,4,4,5,5-hexafluoro-l- 6cyclopenten-1,2-y1enediphosphonate, boiling point 132-134 C, at 0.4millimeter of absolute pressure, with a refractive index n'D of 1.4159.The product contained 27.53 I: carbon, 3.24 hydrogen, 28.90 b fluorine,15.7 phosphorus. The calculated percentages of these elements in C H FOJ, are 27.56 I: carbon, 3.09 hydrogen, 29.07 fluorine, 15.80phosphorus. I

EXAMPLE4 A pressure bottle was charged with 24.5 parts of 1,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene and 75.0 parts of tributylphosphite, sealed, and heated in a water bath for 4 hours at 60 C,followed by 6 hours at C. The consumption of phosphite, measured bytitration of an aliquot with 0.1 N iodine in benzene, was 10.0 partsalter the first heating period and 46.3 parts after the second. Thetheoretical consumption was 50.0 parts. The resulting solution wasdistilled, giving 16.5 parts of butyl chloride, boiling point 8l-83 C,nD 1.3981, and 25.2 parts of recovered tributyl phosphite. Theundistilled residue, 51.9 parts, nD 1.4262, was a viscous liquid whichwas identified by analysis as tetrabutyl-3 ,3,4,4,5,5-hexafluorol-cyclopenten- 1 ,2- ylenediphosphonate. The product contained 11.4phosphorus, 0 chlorine. The calculated percentages of these elements inC, l-I,,F,0,P,are 11.05 phosphorus, 0 chlorine. The product gave apositive test for unsaturation with aqueous potassium permanganate. Ananalytical sample was prepared by distilling a portion of the product at0.004 millimeter of absolute pressure in a Hickman molecular still;boiling point refractiveindex nD 1.4261, density id," 1.19%. The productcontained 45.22 carbon, 6.61 hydrogen, 20.7 fluorine, 10.9 phosphorus.The calculated percentages of these elements in C l- 1 .03, are 45.00carbon, 6.48 hydrogen, 20.34 fluorine, l 1.05 phosphorus.

EXAMPLE 5 80.8 parts of triallyl phosphite and 49.0 parts of 1,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene were reacted togetherfollowing the procedure of Example 1. Tetraally-3,3 ,4,4,5,5-hexafluorol -cyclopentenl ,2- ylenediphoephonate was recovered as analmost colorless liquid, 90.9 parts (92 '5), nD 1.4521, a, 1.2040.

90f 105 Qat 0.004 millimeter of absolute pge sgr e,

The product contained 13.5 k phosphtTruE, 0 '5 chlorine. The calculatedpercentages of these elements in C,,l-I.,,,F,O,P, are 12.48 phosphorus,0 k chlorine.

EXAMPLE 6 A solution of 640 parts of bromine in 1,600 parts of carbontetrachloride was added dropwise over a 4 hour period to a refluxingsolution of 454 parts of tetraallyl- 3 ,3,4,4,5,5-hexafluorol-cyclopenten- 1 ,2- ylenediphosphonate, prepared asdescribed in Example 5, in 3,200 parts of carbon tetrachloride. A heatlamp was used to speed the reaction. From the resulting solution therewas recovered 1,047 parts of tetrakis tetrakis( 2,3-dibromopropyl )-3,3,4,4,5,5-hexafluorol -cyclopentenl ,Z-ylenediphosphonate as adark-colored, heavy oil. The product contained 56.1 bromine, 5.45 I;phosphorus. The calculated percentages of these elements inC,,l-l,,Br,F,0,P, are 56.3 bromine, 5.46 phosphorus. The uptake ofbromine corresponded to the unsaturation in the four allyl groups, thecycloalkene double bond being preserved.

EXAMPLE 7 33.2 parts of triethyl phosphite were added dropwise to 29.5parts of l,2-dichloro-3,3,4,4,5,S,6,6-octafluorocyclohexene at 90-100 C.Little gas evolution was observed. After 10 minutes the reactiontemperature was raised to reflux, whereupon a steady gas evolution wasobserved. At the completion of the reaction the solution was distilled,giving 12.3 parts (37 of diethyl ethylphosphonate, boiling point 52-54C, at 0.5 millimeter of absolute pressure, n"D 1.4111, followed by 25.5parts (51 of tetraethyl- 3 ,3,4,4,5 ,5 ,6,6,-octafluorol -cyclohexen-1,2- ylenediphosphonate, boiling point l-135 C, at 0.4 millimeter ofabsolute pressure, n D 1.4140. The product contained 12.5 phosphorus,0.14 chlorine. The calculated percentages of these elements in C l-5,1 0are 12.45 phosphorus, 0 chlorine. This product is a new compound havingthe structure 33.2 parts of triethyl phosphite were added dropwise to19.5 parts of l,2-dichloro-3,3,4,4-tetrafluorocyclobutene over a 50minute period at reflux (68 C). Gas evolution continued for anadditional hour, following which a test for unreacted phosphite wasnegative. The product was stripped of volatile by-products at 90 C, at0.5 millimeter of absolute pressure, leaving 40.6 parts (100 oftetraethyl-3,3,4,4-tetrafluoro-1- cyclobuten-l,Z-ylene-diphosphonate asan undistilled yellow liquid, D 1.4208. The product contained 36.20carbon, 5.20 hydrogen, 18.95 fluorine, 15.2 phosphorus. The calculatedpercentages of these elements in C,,H,,,F,0,P, are 36.21 carbon, 5.06hydrogen, 19.08 fluorine, 15.55 phosphorus. This product is a newcompound having the structure 0 0 (CiH Ohg (0C2Ht):

EXAMPLEQ pressure, ""0 1.4897, and 11.0 parts (45 5) of recovered1,2-diehloro-3,3,4,4,5,5-hexafluorocyclopentene, The residue wasidentified by analysis as symmetrical diethyldipheny1-3,3,4,4,$,5-hexafluro-lcyclopenden-lJ-ylenediphosphonate, 33.6parts (62 IFD 1.4897. The product contained 11.5 I: phosphorus, 0 I:chlorine. The calculated percentages of these elements in li l- 0,1, are11.38 phosphorus, 0 chlorine.

EXAMPLE 10 EXAMPLEll 23.0 parts of ethyl diphenylphosphinite were addeddropwise over a 20 minute period to 12.3 parts of refluxing 1,2-dichloro-3 ,3 ,4,4,5 ,S-hexafluorocyclopentene, heated an additional20 minutes at 90-l00 C, and allowed to cool. The product, 29.2 parts,crystallized when rubbed with ethyl acetate. One recrystallization fromethyl acetate gave 21.6 parts of 3 ,3,4,4,5,5-hexafluorol-cyclopenten- 1,2-ylene- P,P,P',P-tetraphenylbis(phosphine oxide) as a white,crystalline solid, melting point 176-l77 C. The product contained 60.46carbon, 3.81 k hydrogen, 19.03 '56 fluorine, 11.1 phosphorus. Thecalculated percentages of these elements in C l-i fill}, are 60.42carbon, 3.50 hydrogen, 19.78 fluorine, 10.75 phosphorus. This product isa new compound having the structure 0 O (CIHQIH l mit):

rays,

which compound had been preheated to 120 C before the start of theaddition. The reaction was exothermic. Distillation of the resultingsolution gave 1.5 parts of butyl chloride, boiling point 76.5-78 C, n D1.3991, and 21.1 parts (84 9b) of unsymmetrical dibutyldiethyl-3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2- ylenediphosphonate,boiling point l50l 52 C, at 0.35 millimeter of absolute pressure, n D1.4208. The product contained 40.28 carbon, 5.81 hydrogen, 22.87fluorine, 12.2 phosphorus, 0.1 chlorine. The calculated percentages ofthese elements in C.,H,,,F0.,P, are 40.48 carbon, 5.60 hydrogen, 22.60fluorine, 12.28 phosphorus, chlorine. The product is a new compoundhaving the structure 0 o ommd l wclum Us EXAMPLE 13 This exampleillustrates the preparation of a monophosphoryl cycloalkene compound bythe process of co-pending application referred to above.

49.6 parts of trimethyl phosphite were added dropwise over a 30 minuteperiod to 91.4 parts of l-chloro- 2,3,3,4,4,5,S-heptafluorocyclopentene,with external cooling as required to maintain the temperature between 25C and 35 C. The reaction was exothermic and a gas was evolved. Followingthe addition, the reaction mixture was stirred at room temperature untilthe exotherm subsided, and was then heated briefly to 100 C. A test forunreacted phosphite was negative. The solution was twice distilled,giving a 38 yield ofdimethyl-2-chloro-3,3,4,4,5,5-hexafluoro-1-cyclopenten- 1 -ylphosphonateas a colorless, fuming liquid, boiling point 64-66 C, at 4.5 millimetersof absolute pressure, refractive index n D 1.3817, density d2 1.6669.The product contained 11.1 chlorine, 9.9 phosphorus. The calculatedpercentages of these elements in C H CIF IBP are 11.13 chlorine, 9.73phosphorus. This product is a new compound having the structure.

EXAMPLE 14 448 parts of tetraethyl-3,3,4,4,5,5-hexafluoro-lcyclopentenl,2-ylenediphosphonate, prepared essentially as described in Example 1,were added over a 6 hour period to four liters of boiling 19hydrochloric acid. The rate of addition was adjusted to maintain asteady evolution of ethyl chloride. After the addition, heating wascontinued until the gas evolution subsided (8 hours). The solution wasthen stripped to dryness under reduced pressure leaving 334 parts (99.5of 3,3,4,4,5,5-hexafluorol-cyclopenten- 1,2 ylenediphosphonic acid as ahygroscopic, crystalline solid, melting point l94-l99 C, withdecomposition. The product contained 17.6 phosphorus, 0 chlorine. Thecalculated percentages of these elements in C .,l-LF,0,,P, are 18.5phosphorus, 0 chlorine.

When equimolar quantities of a compound such as tetraethyl tetrafluoro-1 -cyclobuten-l ,2- ylenediphosphonate or tetraethyloctafluoro-lcyclohexen-l,2-ylenediphosphonate are used in place oftetraethyl hexafluoro- 1 -cyclopentenl ,2- ylenediphosphonate thecorresponding compound is formed.

This product is a new compound having the structure The acid was solublein water, ethanol and other polar solvents, and insoluble in hydrocarbonsolvents and in chlorinated hydrocarbon solvents. Titration with 0.1 Nsodium hydroxide solution gave a curve with the appearance of a tribasicacid, with the major inflection point at pH 8.2 corresponding to the 3/4point in the titration.

The acid was converted to its dianilinium salt by ad ding anilinedropwise to a portion of the acid dissolved in acetone. The salt meltedat 267 C with decomposition, after recrystallization from ethanol. Theproduct contained 38.83 carbon, 3.34 hydrogen, 5.47 nitrogen. Thecalculated percentages of these elements in C H F NJJ, are 39.09 carbon,3.47 hydrogen, 5.36 nitrogen.

EXAMPLE 15 A solution of 114.0 parts of3,3,4,4,5,5-hexafluorol-cyclopentenl ,2-ylenediphosphonic acid, preparedas described in Example 14, in 840 parts of phosphorus oxychloride wastreated with 298.0 parts of phosphorus pentachloride in several portionsover a 30 minute period at 30-40 C. Gas evolution was brisk. Thetemperature was then raised to and maintained at 76 C until the gasevolution subsided. Distillation of this solution gave 90.2 parts (65 of3,3,4,4,5,5hexafluorol -cyclopentenl ,Z-yIenediphosphonic tetrachloride,boiling point 89-90 C, at 0.45 millimeter of absolute pressure, whichsolidified on cooling and then melted at 78.581.5 C. The productcontained 33.2 chlorine, 15.2 phosphorus. The calculated percentages ofthese elements in C -,CI,F O,P, are 34.6 chlorine, 15.1 phosphorus. Thisproduct is a new compound, believed to have the structure When equimolarquantities of a compound such as tetrafluorol-cyclobutenl,2-ylenediphosphonic acid EXAMPLE 16 A solution of 29.8 parts of3,3,4,4,5,5-hexafluoro-lcyclopenten- I ,Z-yIenediphosphonictetrachloride, prepared as described in Example 15, in 88 parts ofbenzene was treated dropwise with 29.1 parts of trifluoroethanol over a24 minute period at room temperature. Hydrogen chloride began to evolveduring the addition and subsided after 7 hours stirring at roomtemperature. The solvent was stripped off under vacuum, leaving 43.1parts of residue which gave on distillation 24.6 parts (51 oftetrakis(2,2,2-trifluroethyl )-3,3 ,4,4,5 ,5-hexafluorol-cyclopenten-l,2- ylenediphosphonate, boiling point 84-86 C, at 0.] millimeter ofabsolute pressure, n D L359], freezing at 28 C. The product contained9.2 phosphorus, 1.6 chlorine. The calculated percentages of theseelements in C I-1 13 are 9.3 phosphorus, 0 chlorine.

EXAMPLE 17 A solution of 44.8 parts oftetraethyl-3,3,4,4,5,5-hexafluorol -cyclopentenl ,2-ylenediphosphonate,prepared substantially as described in Example I, in 600 parts ofanhydrous ethanol was heated to reflux in a distillation apparatus.Distillate was drawn off from time to time as required to maintain thevapor temperature at 78 C. when no further depression in the vaportemperature was observed (72 hours), the remainder of the ethanol wasstripped off under vacuum, leaving 40.5 parts of symmetrical diethyldihydrogen- 3 ,3 ,4,4,5,5-hexafluorol -cyclopenten-l ,2-ylenediphosphonate as a slightly yellow, viscous liquid. The productcontained 15.2 phosphorus. The calculated percentage of this element inC H F O P, is 15.8 phosphorus. This product is a new compound believedto have the structure (EH50 0 O 0 can;

Table l illustrates the effectiveness of three of the compounds of theinvention in the extraction of heavy metals. The table shows the percentthorium or uranium extracted from 20 milliliters of 6 N nitric acidsolution containing 200 parts per million of the metal into 20milliliters of a 0.05 M solution of the diphosphoryl compound incyclohexane (or chloroform in the case of the phosphine oxide) after 5minutes shaking on a mechanical shaker. It is seen that the heavy metalswere extracted essentially quantitatively with the aid of the compoundsof this invention, whereas the tributyl phosphate control achieved onlya partial extraction.

TABLE I Percent Metal Nitrates Extracted From 6 N HNO;

Th(IV), U(VI], Extractant percent percent (CIHIO) ,PO 60 72 I s h W) P01H): 100 91 I C0115 C011; 99 99 P o P 0( CsHs0 U 0 CsHl F F:

lot) 1H!) lHI)! Fu: 1

What is claimed is: l. A perfluoro-l-cycloalken l,2-ylene-diphosphorylhalide of the formula 2-" U (KM-l.

wherein X is selected from the group consisting of chlorine and bromine,R is a substituent of the group consisting of alkyl having from one to12 carbon atoms, lower alkoxyalltyl where alkyl contains from one to 12carbon atoms, hydrocarbon aryl having from six to 15 carbon atoms,hydrocarbon aralkyl having from seven to 20 carbon atoms, alltenylhaving from two to l2 carbon atoms, and cycloalkyl having from three to15 carbon atoms, m is from 2 to 4, and n is from 0 to l.

2. Hexafluorol -cyclopenten- 1 ,2-ylenediphosphonic tetrachloride.

3. Hexafluoro i -cyclopentenl ,2-ylenediphosphonic tetrabromide.

i i i 1! k

2. Hexafluoro-1-cyclopenten-1,2-ylenediphosphonic tetrachloride. 3.Hexafluoro1-cyclopenten-1,2-ylenediphosphonic tetrabromide.